Method of dulling nylon and like materials



Aug'. 4, 1959 original Filed May 12. 1954 7 Sheets-Sheet 1 ATTORNEYS Aug. 4, 1959 R. F. STUEWER 2,897,577

METHOD 0F DULLING NYLON ANb LIKE MATERIALS original Filed .May 12, 1954 7 Sheets-Sheet 2 ATTORNEYS INVENTORS Aug. 4, 1959 R. F. sTUEwER 2,897,577

METHOD oF DULLING NYLON AND LIKE MATERIALS original Filed May 12. 1954 7 sheets-sheet s :Elia-z5..

l ATTORNEYS Aug. 4, 1959 R. F. sTuEwl-:R 2,897,577

METHOD OF DULLING NYLON AND IIKE MATERIALS n Original Filed May 12. 1954 7 Sheets-Sheet 4 70 I`\ v Y u? 22 I 7g 21S f 2] Tft- 11' w 73 @g1 7] INVENTORS ATTORNEYS Aug. 4, 1959 R. F. STU EWER METHOD OF DULLING NYLON AND LIKE MATERIALS Original Filed May 12. 1954 7 Sheets-Sheet 5 INVENTORS ATTORNEYS Aug. 4, 1959 R. F. s'ruEwl-:R r V 2,897,577

METHOD 0E DULLING NYLON AND LIKE MATERIALS original Filed May 12. 1954 "l Sheets-sheet e BY MQ@ M ATTORNEYS l Aug. 4, 1959 y R..r. sTUEwER 2,897,577

METHOD OF' DULLING NYLON AND LIKE MATERIALS Original Fld May 12. 1954 7 Sheets-Sheet '7 Jaa" v i T JJ\ BY 2M o# ATTORNEYS United States Patent Q METHD F DULLING NYLON AND LIKE MATERIALS Reinhold F. Stuewer, Scranton, Pa., assignor to Grove Silk Company, Scranton, Pa., a corporation of Penn- Sylvania Original application May 12, 1954, Serial No. 429,244. igiggg and this application April 11, 1955, Serial No.

14 Claims. (Cl. 28-72) This invention relates to an art of performing dulling operations upon the surfaces of fibers such as nylon. The extruded and set fibers of synthetic bers, whether in filament or cut staple form, frequently are too smooth and shining for satisfactory appearance and behavior. The present invention is concerned with a superficial treatment of such fibers to confer a desired dullness or matte appearance thereto, in economical quantity operatlons.

This application is a division of the Stuewer and-Pitman application Ser. No. 429,244, led May 12, 1954.

A feature of the invention is that of holding a yarn of such fibers under tension and for causing the bers to b e 1pressed in contact with particles ofan indenting materia Another feature is that of treating skeins of such yarn by holding them under tension along the bers while kneading the yarn in the presence of particles of an indenting material.

A further feature is that of holding a skein of such yarn under tension, and yieldingly pressing against the yarn while causing the skein to travel through the pressure zone and thereat be subjected to relative movements of the fibers with particles of an indenting material between them.

Other features reside in the performance of a sequence of operations whereby the fibers are converted from a smooth to a dulled surface condition, without entanglement.

An illustrative embodiment of apparatus by which the method may be performed is shown on the accompanying drawings, by way of example, in which:

Fig. l is an upright elevation of the left side of machine structure;

Fig. 2 is a corresponding front elevation with a part broken away; l

Fig. 3 is a corresponding elevation of the right side of machine structure;

Fig. 4 is an enlarged horizontal section substantially on line 4 4 of Fig. 2 with the door open and the upper skein-guiding roller and spray pipe in position for loading or unloading;

Fig. 5 is a corresponding horizontal section substantially on line 5 5 of Fig. 2 with the door omitted and the lower skein-guiding roller being swung to position for loading and unloading;

Fig. 6 is an upright sectional View on an enlarged scale, substantially on line 6 6 of Fig. 2;

Fig. 7 is a conventionalized perspective view, with supporting and certain other parts omitted for clarity, showing the relationship and connection of parts;

Fig. 8 is a diagrammatic View, with parts of a control system in perspective, showing electrical connections.

Commercially available libers contain synthetic materials such as polyamides, and are formed by an extrusion operation from a mass, with subsequent setting followed by a stretching operation which produces orientation within the individual iilaments. Sometimes the original ice 2 mass contains a pigment to reduce the light transmission, and the material is then referred to as a semi-dull or I dull7 dependent on the relative amount of pigment present: but the surface of the material is still essentially smooth as with the non-pigmented or bright filaments.

Such fibers may be used as monofilaments, or several filaments may be twisted together: and a further practice is to cut the filaments into lengths and spin together in cut staple form. Thekpresent invention is applicable to the various forms and sizes, and produces an effect distinct from that attained by incorporated pigment.

For illustrative comparison of sizes, it may be stated that nylon yarns are presently commercially available and used in quantity for stockings and knit goods in the following typical sizes:

The main mechanical structure is supported by four pipe legs 20 connected by welding to angle irons 21 and a front iron 22 providing a horizontal stand upon which is mounted a housing having the side walls 24, 25 and the rear wall 26. The lower part of the front of this housing can be closed by a door 28 on hinges 29 and having a latch 3i) for securing it in closed position: it is preferred to have the lower edge 31 of the door bent inwardly so that liquid is deected inside of the front iron 22 and delivered into the catch basin or sump S which is conventionally shown as a liquid-tight box mounted on wheels 33 so that it can be withdrawn through the front pair of legs 20, its position being controlled by the front stiffener 34 which *extends upwardly and vengages the front iron 22.

At the top of the housing formed by walls 24, 25, 26 is mounted a control housing CH described in detail hereinafter. Also mounted at the top of the housing 24, 25, 26 are ya pair of .upwardly 'extending pipes 35 which are held rigidly in upright position by straps 36.

At the left side of the machine (Figs. l and 4) ahorizontal supporting member 38 extends from the wall 26 and is connected to the upright member 39 to provide support for valve and pipe structures as described hereinafter. Angle braces 40 likewise serve to 4brace the pipe connections.

This frame structure supports the moving parts.

The walls 24, 25 have pivots 42 for supporting the lever arms 43 of a rocking sub-frame, these arms being outside of the walls 24, 25 and supporting the shaft 44 of a lower pressure roller 45 having a smooth rubber covering 46 (Fig. 6). The shaft 44 can move upward and downward in the elongated apertures 47 of the walls 24, 25. The shaft 44 has connected thereon the sprockets 48 which in turn are connected by chains 49 with the sprockets 5t) carried by the rear driving shaft 51 which passes through a speed reduction unit 52 which il1ustratively is of commercial type and has a shaft 53 extending rearwardly and supporting a pulley 54 for belt 55 which is driven by pulley 56 of the `driving motor DM. This motor DM is supported by struts 57 connected to a crossplate 58 rigid with the arms 43. It will be noted that the weight of the motor and its struts, the weight of the reduction unit, and the bearing parts act to cause the sub-frame to rock clockwise in Figs. 3 and 6, about the pivots 42, thus moving the lower pressure roller 45 .direction by the cams 65 (Fig. 6) which are fixed on a cam shaft V66 journalled -on the support irons 21 vand having (Fig. 3) a worm wheel 67 presented for meshing engagement with the worm 68 on a shaft'69, likewise car- ,n'ed by bearings on the irons 21'and on the posts 20,

and having a crank handle Y69a at the front of the machine. i l

The left-hand housing wall 24, in the illustrated form, supports a swivel bearing 79 (Figs. l and 5) for the end of a second pressure roller 71 which likewisehas a smooth surface jacket 72 Vott rubber. This bearing 70 permits the roller 71'and its jacket 72 to rotate, and also permits it to be swung (Fig. out of the housing. When swung back into operating position, the right-hand end of the shaft 73 of the roller engages in a notch 74 formed in the wall 2S (Fig. 3); and its axis is then parallel to the axis of the lower pressure roller and the shaft 44 of the latter. In this working position, the weights on the sub-frame cause the arms 43 to rock clockwise so that the lower pressure roller is in contact with the second pressure roller 71 Yor `with yarn vskeins passing '80 (Fig. `6) which is mounted at its upper end on-a threaded stem 81v extending through the end cap 82 of the pipe and adjustable in position by the nut 83. The lower end of the spring is connected to a drag link 84 which in turn is connected to a bearing 85. The two bearings 85 support the shaft S6 of an upper tension roller 87 which may have a smooth metal surface. A bracket 88 extends forwardly from the housing Wall 24 and has a sleeve member 89 iixcd thereon for receiving (Fig. 4) the left-hand end of the shaft86 when. the parts are in position for loading, noting that the bracket 38 is located vbelowfthenorrnal level of the shaft S6 (Fig. 6) when the latter is in its tensioned operating position.

The support 38 (Figs. 1 and 4) carries three valves 90, 91, 92 which are connected to a manifold pipe 93 supported in part by the angle braces 40 and leading to the distributing pipe 94 from which extends a horizontal spray pipe 95 located (Fig. 6) just inside of the rear wall 26 of the housing and having orifices directed relatively downward and forward for delivering a liquid spray 97 as described hereinafter. The distributing .pipe

94 is also connected through a swivel joint 98 with a l second spray pipe 99 which terminates short of the end wall 25 of the housing, so that it may be swung (Fig. 4) out of the housing during loading and unloading operations. i

Limit ngers 100 are provided for preventing disengagement of skeins during the loading operation, being illustratively supported by the back wall 26. Preferably the spray pipe 99 has upwardly and rearwardly directed openings so that a liquid spray 101 is delivered therefrom as described hereinafter.

The door 28 has separators or guide fingers 105 fastened on its rear or inner wall (Figs. 4 and 6), and thus projecting between skeins of yarn when the door is in closed position.

The housing CH at the top of the structure has a tightly-closing access door at its front, and contains and protects electrical elements that determine a sequence of operations.

In Figs. 7 and 8 are shown conventionalized parts of the structure connected to illustrate the operation. A supply of satisfactorily pure water under pressure is delivered through a pipe to the valve 90. A Soaping solution is prepared in a soap solution tank ST having a motor-driven pump STP connected for takingthe solution from the'tank and delivering itthrough ahose 121 to the valve 91. Correspondingly, an oil emulsion is prepared in an oil emulsion tank OT having a motordriven pump OTP which takes the oil emulsion from the tank and delivers it through the hose 122 to the valve 92. The valves 90, 91, 92 have respective solenoids WVS, SVS and OVS which vupon energization serve to open the respective valves.

A timing motor TM is connected through speed reduction gearing 125 to drive a timing shaft 126 having thereon a number of cams'MC, WC, SC, OC and RC cooperative with corresponding switches MS, WS, SS and OS which are normally open but are closed upon presentation of a cam notch, and a switch RS which has` both normally openV and normally closed contacts selectively closed and opened by the notches and humps on cam RC. The master cam` MC has illustratively a single peripherally short notch for operating the master switch MS. A manual switch S1 is connected in parallel to switch MS, so that when switch S1 is closed current tiows from one mains conductor 130 through the mains switch S2 and the switch S1 to the bus'conductor 131 thereby energizing the timing motor TMso that it runs; the current then returning to the other mains conductor 132. As thetiming-motor-rotates `the shaft 126, the master cam MC operates switch MS and closes the circuit so that the flow from conductor to bus conductor 131 is main- .tained regardless .of the position-of switch S1, which is then permitted to open.

In the illustrative showing, a` l5 minute cycle of operation Vis established by the gearing 125, so that the motor TM rotates the shaft 126 once in l5 minutes. At the beginning of rotation of the shaft 126 only the master switch MS lis in operation, and therewith the reversing cam RC is yholding the reversing switch RS with one circuit open and the other circuit closed through the conductors 133, 134 leading to the coilsvof the reversing relays RRa, RRb so that current from the mains conductors 130, 132 ilows throughra relay RRa or RRI: and by conductors to the driving motor DM, causing this motor to start and turn in one direction. The relays RRa and;RRb are mechanically interlocked, as conventionalized by the element RRx, so that they cannot be simultaneously energized: such grouped relays are .commercially available and no further detail .of structure *RS acts to open and close the circuits of the conductors 133, 134 so that the other reversing relay RRb or RRa -is actuated whereby the drivingmotorDM is then caused to run in a reversed direction for another period of time until the reverse cam RC actsagain. Illustratively, this reversal occurs at each 3() seconds Vof time, with the vmotor DM thus turning-for SO-secondsin one direction and then turning for 30 seconds in theopposite direction.

In the illustrative cycle, the water controlling cam 'WChas two depressions, the-first of which procures operation of the watervcontrolling switch WS after the shaft 126 has been rotated for a distance corresponding to 10 -minutes and 30 Vseconds of time, closing the normally open contact of this switch so that current -ows from the'bus 131 through switch WS to conductor 135 and thus to the water valve solenoid WVS, opening the valve -90-so that water flows from the conduit 120 through the manifold 93 and is sprayed'from the pipes 95, 99'upon ythe skeins of yarn which are passing over the tension I90 is closed.

Immediately lfollowing the wetting operation just described,tl 1,e soap solutionfcamSC presents its single de pression to its switch SS, with closing of the normally open contact thereof, so that current flows from the bus conductor 131 through the switch SS and'by conductor 136 to the solenoid SVS thereby opening the valve 91 so that the soap solution is permitted to ow from the conduit 121 through valve 91 and manifold 93 and be sprayed from the pipes 95, 99. In the illustrative cycle, this continues for seconds, and the cam SC then opens the switch SS again, thereby eifecting closure of the valve 91.

Thereafter, for 2 minutes, the master switch MS acts in :conjunction with the reversing switch RS to cause the driving motor DM to continue running for 2 minutes, with the aforesaid periodic reversal being accomplished by the action of switch RS upon the current supply to the relays RRa, RRb. A

After 2 minutes of running with the soap solution in the iibers, the second depression on the water supply cam WC is presented to the switch WS which closes, and current again flows through conductor 135 to the water valve solenoid WVS, and valve 90 opens again and remains open for 21/2 minutes, wherewith water flows from the conduit 120 to the manifold 93 and the spray pipes 95, 99; and the abrasive material 'is washed from the yarn fibers. Du-ring this time, the switches MS, RS are in control of the driving motor DM, so that the same continue to run with the aforesaid periodic reversal.

Thereafter, the cam OC which controls the delivery of oil emulsion presents its single short depression to the oil emulsion controlling switch OS, with closing of the contact therein so that current flows by conductor 137 to the solenoid OVS of valve 92, and the valve 92 opens so that the oil emulsion in conduit 122 ows through valve 92, manifold 93, and from the spray pipes 95, 99, wherewith the fibers are oiled. After this has continued for l0 seconds, the cam OC causes the switch OS to open again, and the valve 92 closes. Simultaneously, the single depression in the master cam MC cooperates with the master switch MS to open this switch, so that Current no longer iiows from mains conductor 130 and bus conductor 131 and the timing motor TM stops: simultaneously, supply of current to the various switches WS, SS, OS, and RS fails, so that'accidental operation of the solenoids WVS, SVS, OVS cannot occur, and also the reversing relays RRa, RRb remain in open positions so that the motor DM is brought to and held at a standstill.

It is preferred, for operation of a single machine from the soap solution and oil emulsion tanks ST, OT, to connect the respective pump motors to the conductors 136, 137, so that the pump motors STP, OTP a-re operated concurrently with the opening of the valves, nicety of control being effected by the quick action of the valves 91, 92 in closing.

To permit quick stoppage of the system if desired, a manual switch S2 is provided in the conductor 130.

In operation of the machine, with the machine empty, an abrasive slurry is prepared and skeins of yarn dipped and worked therein for receiving charges. The upper tension roller is removed from its bearings 85, and the left-hand shaft end 86 is introduced into the holding bracket 89, with the door 28 open (Fig. 4). The spray pipe 99 is swung outwardly to the position of Fig. 4. The lower pressure roller 45 is moved downward by turning the crank 70 so that cam 65 (Fig. 6) engages the bottom of the sub-frame structure 43, 58 and lifts the same: thus relieving pressure from the upper pressure roller 71. The upper pressure roller 71 is then swung outward about its bearing 70 to the position of Fig. 5. Skeins of yarn are then threaded onto the rollers by passing them around the tension roller 87, the spray pipe 99, and the pressure roller 71, arranging them closely against one another along the length of the tension roller 87, wherewith the left-hand finger 100 serves to prevent these skeins from being moved beyond the ends of the rollers. In the illustrative practice, with rollers having a length of 24 inches, 24 skeins of the commercial 2 ounce size are employed. The pressure roller 71 is then swung back into the housing and engaged in the notch 74, carrying the lower ends of the skeins with it. The upper or tension roller 87 is taken from the bracket 88, 89 and its ends engaged in the bearings which can be pulled downward and outward for the purpose: upon re,- lease of the traction links 84, a tension is established in the skeins of -yarn as these are stretched upward by the movement of the tension roller 87 .upward and away from the pressure rollers, the skeins being controlled against endwise shifting by the fingers supported from the rear wall 26 at about one inch from the end planes of the rollers. The spray pipe 99 is swung into its position of use (Fig. 6).

The door` 28 is now moved toward closed position, until-its guidemembers approach the skeins of yarn. By hand, the left-hand four skeins are separated so that their outer and downward flights, at the left in Fig. 6, come between the first two guide members 105. The next four skeins are likewise parted so that they come between the second and third guide members 105 and so forth. The door is partly closed at each separation, so that the skeins are held. The door is closed and latched. It will be noted that this latter operation is facilitated in that the upper edge of door 28 is below the position of fingers 100, so that a substantial part of each skein is accessible above the door edge.

The crank 70 is again rotated so that the cams 65 release the rocking sub-frame, and the pressure roller 45 is permitted to move upwardly under the weight imposed by the driving motor DM, and other parts of this sub-frame, until it comes in yielding engagement with the skeins at their lower bights, and forces these against the pressure roller 71.

The cycle of operation is then started by closing thc switch S1, and the operation occurs as described above, wherewith the rotation of the driving motor DM causes the lower pressure roller 45 to be rotated while in contact with the skeins of yarn, so that the same are caused to travel; during the counterclockwise rotation of the roller 45, the outer or front iiight of the skeins of yarn moves in an upward direction, and upon reversal, with the. clockwise rotation of the roller 45, the outer or front flight moves downward in Fig. 6. The lower pressure roller 45 yieldingly presses the yarn against the upper pressure roller 71, and the latter turns. 'Ihe tension upon the skeins may be regulated by adjusting the nuts 83.

During the described cycle, the driving motor DM operates for lOl/z minutes, with reversal of direction every 30 seconds, and during this time the kneading effect of the rubber-covered pressure rollers 45, 71 upon the fibers in the `skeins causes these bers to move relative to one another with the abrasive particles therebetween and indentation is produced upon the surfaces of the iibers but with no signiiicant wearing away or gouging out of material. During this action, the water vehicle of the slurry is partly squeezed out and drops into the sump S; wherewith the initial action is in the presence of a greater amount of moisture than the action toward the end of the period. Thereupon, water is admitted for 10 seconds to restore wetness to the passing yarn, followed by the delivery of a Soaping solution for 10 seeonds and then running in the presence of the soap solution for 2 minutes, wherewith the particles become loosened if embedded in the surface of the ber. Thereafter, a continued running occurs with a water spray for 21/2 minutes, resulting in the washing of essentially all particles from the yarn. In each phase of operation, the liquid flows downward and enters the sump S. Finally, an oil emulsion is delivered for l0 seconds, therewith coating the fibers and permitting, after drying, of knitting these oiled fibers without difficulty.

As the .motor DM turns in a clockwise direction, 'for example, the relative movements ofthe fibers as they pass between Vthe Ypressure rolls 45, 71, and the difference in length between the turns of yarn at the inner and outer sides of a skein, tend to cause irregularity or bunching: but the following reversal compensates for establishing a proportioned correcting effect in the opposite direction: and in practice it has been found that the yarn can be un- Wound from the skeins without difficulty.

Among the materials satisfactory in particle form are powdered calcite, very finely powdered glass and diatomaceous earth. Fine sodium bicarbonate crystals have been employed and, in general, any insoluble or limited ly-soluble material of proper particle size may be used, which has the hardness property of producing the indentation. In general, materials havinga hardness .of 2 or more on the Moh scale can be'used, for example linely groundtrock salt or harder substances; with dominant preference for materials inrparticles having sharp corners or edges. satisfactory for the dulling or delustering operation, and the observation has been made that the'particles are broken up and comminuted during the treatment.

The hardness of such appropriate materials cannot be directly compared to the hardness of nylon, for the reason that the nylon behaves somewhat like a metal in having ductility and capability of being dented, and ialso has an elastic -rubbery quality. For example, when two 40 denier monotilaments of nylon are crossed and pressed between two glass plates, each is iiattened at the intersection until its dimension decreases in the vdirection of the pressure and its dimension transverse to the pressure increases 50 percent: when the pressure `is released, each filament tends toregain its shape, for example losing half of the transverse increase in diameter. Thus a Brinell test for hardness of nylon gives an exaggerated result as compared with a Rockwell test. As further examples of behavior, if an unstretched mass of nylon plastic is pressed by a needle point, a depression is formed with a raised rim around it, which recedes partially when the needle is removed; and if the needle is drawn along the surface, under pressure, a furrow is formed with a central groove and raised edges but no material is vremoved. Likewise, pressing a layer of tine rocksalt crystals against an originally smooth and shining surface of a block of unstretched'nylon causes indentation, but without removal of material even if the crystals are displaced by rubbing; and the surface after removal of the material exhibits loss of the original shine. It is to be remarked, further, that nylon filaments have been stretched during manufacture, and have attained an oriented crystal structure, as compared to the random arrangement in the funstretched mass, so that the relative hardness of Diatomaceous earthhas been found highly the filament cannotY be determined by computation from tests made upon the mass.

Slurries are formed therewith containing about 20 percent of the indenting particles, noting that the proportions may be modified within the limits of having a slurry which is too thick to enter between the tibers during the preliminary loading operation, or one which is so thin that it drains away without depositing the particles ready for operation. The vehicle for the slurry'can be selected from a wide range of liquids which are inert relative to the nylon. Water is a cheap and desirable vehicle for materials insoluble therein, such as calcite, glass, diatomaceous earth: and can be used with Watersoluble materials such as rocksalt, sodium bicarbonate, or the like, in the form of a saturated solution of the material being used.

The solids content of the slurry, for optimum effect, varies with the material used, the particle size, and the vehicle. In general, it should be in the range of 8 to 4() percent. With diatomaceous earth, a slurry of 12.5 percent `by weight in water is satisfactory, and therewith in the illustrative example about 2O percent of the material, based on yarn Weight, is taken up by the yarn: the particles tend to be ltered out by the yarn and remain enmeshed in the skein, While the Water is squeezed out. A general range of 8 to 16 percent in a water slurry is preferred for diatomaceous earth, noting that with less than 8 percent, the dulling action is very slow, while more than 16 percent may cause an uneven treatment as the water vehicle is squeezed out and the presence of an excess of material in the skein leads to matting and a low amount of relative movement. With silica and non-friable materials, enmeshing was more regular and more than 40 percent could be present in the slurry, with a preference for 20 to 40 percent.

During use of the material, it has been found that the presence of a greater amount of particles, other conditions being constant, will give a greater dulling effect up to the point at which the total mass is relatively stiff and corresponds to the yarn iibers being embedded Within an essentially solid mass of particles so that little relative movement of the fibers can occur.

Using a silica powder, commercially designated as passing a 325 mesh screen, in determining the eiects of the sizes thereof, it was found upon microscopic examination, the original powder exhibited a few particles as large as 40 microns. When such a powder was fractionated by repeated settling, an intermediate fraction was more effective than the smaller sized fractions. Fractions were used in dulling experiments, using 20 percent by weight of the dry yarn, sprinkling evenly over the wet yarn and distributing by working with the hands. The working time was 15 minutes. The results were as follows:

N ern-The reflectance values are those determined as set out below, as a preamble to Table III.

Table I `A Reflectanoe Values-Black Yarn Particle Visual Dulling Perpen- Percent Parallel dicular Ratio Drop Sample Size Control 0. 0055 0.17 30. 9

less than 5-.. least Not Determined 3- more than 1- 0. 0068 0.14 20. 6 33. 3 ll5. more than 2- 0. 010 0.13 13. 0 57. 9 20-25- same as 3 0. 010 O. 13 13. 0 57. 9

The size for Samples 1-4 is stated in microns. Micro- 15 scopically examined, Sample '4 contained some particles as large as 40 microns and a few as small as l5 microns. Samples 2 and 3 were quite uniform.

A powdered calcite, designated commercially as having 20 an average large particle size of 25 microns, was more effective than one with an average size of 5 microns in work upon nylon fibers which were denier or over. Upon microscopic examination, the micron material was found to have some particles as large as 100 microns but 25 most were in the 1060 micron range. The material was fractionated by settling; for a fraction A with most of the particles in the range of 10 to 30 microns, and a fraction B in the range of 40 to 60 microns with some par- 30 ticles as large as 100 microns. It was employed as with the silica powder. Some grinding of the calcite occurred during the dulling: but many large particles still remained. The two fractions gave essentially theA same result, with values of 0.73 for parallel-plane viewing and 0.84 for perpendicular-plane viewing of the undyed specimens: no tests were made with dyed yarn. These values represent a change of ratio from 1.37 in the control to 1.15 of the treated material, with a precentage drop of 16. Thus,

the results are comparable with those for silica powder as set out in Table I.

In further experiments, a residue from the glass polishing industry was used (commercially available by the name Gartex). particles, but contains some particles larger than those with the silica described above: the results are comparable. Being commercially designated as having a particle size of 25 microns, it was fractionated by repeated settlings in water. Fraction A contained particles largely between 5 and 10 microns, a few being as large as 15 microns and some smaller than 5 microns. Fraction B was quite uniform in the range of 20 to 30 microns. Fraction C was largely particles above microns, 55

some being as large as 100, while a few were as small as 20. Single skeins were run for 15 minutes. Fraction B gave better results than fractions A or C. Fraction A was least effective. There was no conclusive evidence 60 A portion of the yarn was knitted into fabric and dyed:

there was no stitch distortion or uneven dyeing as would be present in damaged yarn. A test of breaking strength showed about 7 percent loss. The samples were compared visually, with the samples of Table IV below, as-

This material consists of silica and glass 45 signing arbitrary dullness values of 1, 2 and 3 to the 10, 2O and 30 minute samples. The results were:

To determine the effect of large particles, an emery powder was employed having particles in the range of 300 microns with a few having a dimension as great as 500 microns. Single skeins were run under the conditions described for the machine above, and then under increased pressure by use of the metal tube with the thin rubber sleeve. Very little dulling effect =Was observed at the lower pressure, but at the higher pressure a fair dulling occurred but with a great dealof damage. Upon examination, the fiber was grossly distorted in many places. In some places it was flattened, and at many spots it was completely broken or cut through.

Thus, the optimum particle size is somewhat dependent upon the pressure employed. With the stated pressures of around 1000 pounds in the described machine, the optimum particle size is around 20 microns for non-friable materials when l5 denier nylon is being treated: with a preferred range of 10 lto 30 microns with iilaments of l0 to microns diameter. The maximum size of particles, to avoid damage, appears around 150 microns for uses upto 70 denier. In operation, there appears no advantage in the use of the larger particles, and thereis some diilculty with them as slurries tend to settle very rapidly and are more diilicult to apply uniformly and remove completely.

The diatomaceous earth is a composite of shells and fragments of disk and needle shape, with disks up to microns diameter and needles up to micron length and 5-20 micron diameter. In practice therewith, it has been noted that, while the original material settled rapidly in water, the spent slurry after a iirst indenting operation was much slower in settling, indicating that the individual shells had broken during the operation, thus affording many sharp edges, a conclusion supported by microscopic examination. The commercial material employed is designated as having an average particle size of 7-9 microns, but microscopic examination has indicated the above range.

There are relationships between the unit pressure upon the nylon filaments and between the amount of indenting material present, and the largest permissible size for optimum eiiects. Assuming that the libers are cylinders of the same size, and parallel and closely packed, the area of unoccupied space in a cross-section is about 10 percent of the area occupied bythe fibers. A spherical particle of 1/6 the diameter of a filament, if placed in a space, ywill touch the surrounding filaments and represents a maximum dimension which in the assumed case causes no filament displacement. On the quantity basis, tightly packed powdered silica has a density of about 1.5 times that of nylon, so that the 10 percent voids can receive powdered silica up to about 15 percent of the weight of successive lingers.

the shining or mirrorlike surface appearance is replaced p by a sheen, noting that very line abrasives are used toY polish optical lenses of glass.

The pressure employed is distributed by the rollers over the skeins and the individual laments, ,It has been found Vthat'vthe `pressure. can bepracticallydetermined for optimum eifects upon the basis of the number of skeins present. ounces each, and 4 inch rollers, a total pressure of 500 pounds gives much. less effect in 21 minutes than 1000v pounds in lOl/2 minutes.

The above illustrative example, with a totalV cycle of .15 minutes, was effective with 15 denier monoiilament yarn. By comparison, a l2 denier monolament yarn'was successfullyrtreated to a like dullness with the same timing ,forfthelater.operationsbutwith 151/2 minutes employed in the iirst'step of working with theindenting particles.

It may bestated, generally, that with proper pressure the. dulling effect israpid atiirst andthen increases more slowly. With the instance of l5 ,denier yarn ina l5 minute cycle including action in the presence of the indenting materialfor i/z minutes, to give a commercially acceptable appearance, an increase to minutes in the dulling sub-cycle gives a greater effect, while an increase to minutes for the sub-cycle gives only a slight further efectother conditions being kept the same. A 2 ounce skein contains over l0 miles of yarn; the treatment for lOl/z minutes causes far less than one break per skein during the subsequent unwinding-a result in which the frequent reversals appear a great factor.

In Van illustrative machine, the rollers 45, 71 and `87 were 24 incheslong, and 24 skeins; each of 2 ounces of nylon, occupied 22 inches between'the outer guide lingers 105, being grouped 4 skeins between each two Thehousing was about 8 inches between the door 28 and the back Wall 26 andrabout 30 inches high from the lower edge to the lower ends of the tension spring pipes 35. The lowerpressure rollers 4S, 71 were each 4 inches in external diameter, with a exible rubbery covering (the material commercially available under the trade name neoprene, Shore A durometer -test 55-60, is satisfactory) about 1A vinch thick. The

upper tension roller 85 was made ofaluminum and 3 inches in diameter. The axis of the lower pressure roller 45, inthe absenceof yarn,-Was about 23 inches below the Vtop of the housing. VWhen in operating position, the axis of the pressure and tension rollers and ofthe spray pipe 99-were in a vertical plane located about 6 inches from the rear wall 26. In this machine, the

`lever `arms 43 supported vthe lower roller 45 with its axis about 31/2 inches from the fulcrum point 42, and

. the total weight acting on the rear end of arms 43 was about 200 pounds at a fulcrum-distance of about '16 inches, thus representing a pressure of about 1000 `pounds atthe lowerpressure roller 45, or about 45 pounds per effective inch of length of this roller.

In the abovedescription of results, stated as loccurring .with increasedV pressure, the effect corresponded to about an eight-fold increase.

Other practices, for example with 40 denier monolament yarn and 70 denier 34'lament yarn, have produced good dulling effects respectivelyin 10 minutes and l5 minutes under the pressure and other conditions stated above for the illustrative machine and practice.

The operation is one of indentation rather thangabrasion and removal'ofmaterial. Weight studies upon the yarn, comparing Weights before and. after treatment,y indi- .cate thatverysmalllosses occur from the fibers and la- In the illustrativemachine, with 24 skeins of 2 ments. Likewise,- strength trials indicate that there is a ymaximum reduction in tensile strength (6 inch pieces) of ,5 percent. The values of strength vary from skein to skein as received from the manufacturer,V and the observed differences are'well within the range. Optically, at low-magnification, the ber surfaceshave-an'appearance as though blasted with very line sand: at higher powers and in a dark field, small light arrows appear and Vare believed to indicate the great irregularityof the surface. lUsing ,thepreferred siliceous particles, the product had the scroopy feel of silk.

. The dulling effect can be numerically measured by a reflectance meter,'most suitably with the yarn dyed black and by comparison to anuntreated yarn. The samples Ashould `be thoroughly clean, and made into `skeins of sparallel threads, or V'better into seriplane panels (on dull vvblackcardboardV as a background) containing for example with 15 `denier nylonatleast 800 threads vper inch, and corresponding numbers of threads for other deniers. ForV accuracy,'therbackground and the-number yof threads per inch should `be the same for the controland the Atreated specimens. Employinga Welch Densichron device with a 45.degree reflectance head, which was adjusted L and calibrated-for.reflectance values in the gray scale of I.C.I. y. tristimulus values for illuminant C, based on lmeasurements with'the G.E. recording spectrometer, the standards were small test pieces, with one side glazed and `the other side unglazed, varying from white through livariousshades of gray to black. v-ln use, a light beam `strikesthesample at an=angleof.45 degrees: light which isreflectedas from a planemirrorl is notmeasured, and .azperfect planemirror would give a zero reading. Light `'which visscattered ordeected is read by the electric photometer atan angle of degrees. The effect differs according :to the-angle of the plane of the beam: when the beam plane is perpendicular to the axes of the threads, the values for dulled yarn are less than for the control: when the beam plane 'is parallel, the values for dulled yarn 'are greater than for 'the control. The apparatus used Iwas constructed lto operate at three scales of sensi- `tivity,.a.decimally related: the diiference between untreated yarn and dulled yarn was apparent ata coarse setting, lwhile the differences between yarn treated for `20` and'30 minutes required resort to a more sensitive v scale.

YIn generaLit was found-'that the values (black-dyed specimens) with parallel light increased up to 250% upon dullingttreatment undercommercially satisfactory conditions; an increase of 25 -percent is a minimum for practical purposes; Withvaluesof increase of 50 to 150 per- Acent representing desirable and `sufficient effects. Correspondingly, with perpendicular light, the same specimens showed decreases up to 70 percent: a 20 percent decrease is lrequired for commercially useful effects; decreases of 25 to '50 percent representing desirable and suiiicient .elfects The change of ratios of readings withparallel and with ,perpendicular light, for the control and for the treated specimens,vis particularly characteristic.

In general, the ratio for the treated yarn should be at least l5 percent and preferably 30 percent less than with the control; ratio changes as high as 90 percent havebeen observed. The ratio decreases with the durationcf treatment, other factors being the same, but is notl linear with time. With black-dyed specimens, in seriplane panel tests at least a 10 percent drop of the ratio, comparedwiththe control, is required for commercially useful effects: with white (undyed) skein specimens, the

drop of ratioshould be 10 to 70 percent for commercially useful eects; and, with black-dyed skeins, at least 25 percent.

YIt may be remarked that nylon itself usually contains .-a pigment as dulling or opaquing agent, often white. .When tests were made with such light-colored yarns (sometimes called .dull or semi-dull according to the amount ofpigment present), the general illumination effect tends `to obscure the results. 'For instance,

ver

13 by mounting seriplane panels on a black cardboard, with 2400 -threads of 15 denier per inch, results were obtained with white yarn:

Noting that the light perceived by the apparatus depends upon the color of the specimens, the following results `of tests with 15 denier white semi-dull nylon, untreated (control) and treated for l0, 20 and 30 minutes with diatomaceous earth yare indicative, Ithe samples being made up into small skeins containing 800 iibers each, with one lot tested in the original color (White) and another lot tested after dyeing black:

Rdg signiiies the apparatus reading; Percent Inc. the percentage increase of reading over that for the control; Percent Dec. the corresponding percentage decrease; and Percent Drop of Ratio the percentage drop from the ratio found for the control specimen.

Table IV-A White Samples (undyed): coarse scale Parallel Light Perpendicular Light Percent Ratio Drop of Ratio Rdg Percent Rdg. Percent Inc. ec.

Control 0. 87 1. 2 1. 4

These results are comparable to those of Table III; noting that Table III is based upon white seriplane panel specimens and Table IV-A on White skeins.

That the result comes from the dulling is shown by performing tests upon nylon which had been dyed blueblack before the treatment, -as shown by the following:

Table V Light Beam Plane Ratio Parallel Perpendieular Control l 010 0. 17 17. 0 Dulled 0.016 0.10 6.0

Further illustrative is the following result, produced by a far-reaching treatment of l5 denier yarn of the socalled semi-dull type. Diatomaceous earth was used.

Table VI Parallel Perpendicular Drop,

Ratio Percent Rdg. Percent Rdg. Percent Inc. Dec.

Control 0.006 0.17 28 Dulled 0.022 266 0.065 67 3 89 The treated specimen of Table VI was dulled beyond commercial requirements: Wherewith the ratio dropped by 89 percent.

Tests made with so-called bright commercially available yarn, which contained no pigment, and was of 70 denier size, gave the following result on meter readings of small skeins containing 200 threads.

Table VII Parallel Perpendicular Percent Ratio Drop Rdg. Percent Rdg. Percent Inc. Dec.

Control-white 0.60 V2.7 4.5 Sample-white 0.85 25 1.7 37 2.0 55.6 Control-black 0.005 0.13 26 Sample-black 0.010 0.10 30 10 61.5

'The values indicate that the effect has occurred, and the results with the dyed specimens are parallel to those obtained with so-called semi-dulled yarns.

The results in the tables show that apparatus can be employed in determining the existence of the effects and the regular course of the treatment; and show the possibility of specifying the treatment effect to be attained. In actual practice, visual comparison can readily be made by a person skilled in the work, by merely viewing seriplane panels with proper lighting. Comparisons of specimens thus made agree well with yapparatus measurements.

A further manner of determining the eifects of the treatment is by comparison of the rate of acceptancel of dye after successive stages of treatment, with use of the reflectance meter and its gray scale of standards. When the dulled yarn and an undulled control were dipped for 5 minutes at 100 degrees F. in a 0.1 percent solution ofa black dye (Glycolan Black B), then Washed well with soap, and dried, the observed results are deiinite and refproducible. Illustrative of this is the following, representresults obtained with a parallel beam:

Since the values in Table VI are based upon material of like history, the variance in dyeability by heat treatments and other prior history of the nylon yarn is exluded.

The difference in the effect of dulling in the present manner and that by incorporating pigment into the lilaments for absorbing or scattering light, can be illustrated by the behavior upon dyeing. When the `so-called dulling is attained by incorporated pigment, the effect is essentially lost when the filaments are dyed black, because the surface luster has not been changed: lbut with yarns treated in the present fashion, the effect is more striking after dyeing to very deep shades.

The eilects upon the yarn are the production of an increased rate of dyeing, a change in the feel of the yarn to produce a scroopy hand, `a decreased coeihcient of friction toward smooth surfacessuch as porcelain guides,

along with the decrease in gloss or luster.

andY (3) -thevduration of treatment.

.There is a.correlation betweenthe pressure and time,

but the relationship is not inversely linear. For example, With a force of 500 pounds upon the rollers-ofthe -described machine, Vthere Waslittle dulliug in 1 0 minutes yand a multiple ,of this time is required to attain a satisfactory effect: a satisfactory dulling was yattained in l -minutes with a force of 1000 pounds, whereas 750 poundsgavea somewhat lesser eifect. These values correspond to .pressures of 20, 30 and 40 pounds `,perlinch of length of the rollers, or per skein V of yarn.

The change in dyeing properties is indicated by `the behavior with acetate dyes, in which the maximum change of rate appears to occur before the maximum dullness is reached.

It willbe understoodY that the illustrative practice of the invention isnotrestrictive: and that the same may be employed in -many Ways withinthe scope of the appended claims.

YWhat is claimed is:

l; The method of dulling nylon and like bers which comprises supplying a tinely divided'moistened indenting material into a mass of the iib'ers, passing the total mass 'lbetweenpressure rollers, at leastone said roller having aresiliently yielding surface whereby to procure a kneading action of the bers and indenting material, and repeatling the passage until the surfaces ofthe fibers .have receivedindentations over their areas.

2. 'The method of dulling nylon and like fibers which comprises supplying -a slurry of finely divided indenting material to and into a mass of the bers, passing the Atotal mass between pressure rollers, at least oney said roller having a resiliently yielding surface whereby to procure a kneading action of the ibers and indenting material, and repeating the passage with alternation of the direction `ofypassage from time to time until the surfaces of the bers lhave receiver indentations overtheir areas.

3. The ymethod of dulling 4nylon andlike'iibers in skeins, which comprises supplying a slurry of finely divided indenting-material to the fibers inthe skein, stretching the skein Aloop over a iirst pressure roller, applying pressure -tothe `tibers in the loop by coaction of a secondpressure rollerwith said -iirst pressure roller, at least one of said pressure rollers having a yielding surface `whereby a kneading and relative displacement of the iibers is produced, rotating one of the pressure rollers successively in alternative directions, and continuing the pressure and alternative rotation until the surfaces of the fibers have received indentations over their areas.

4. The method as in claim 3, including the step of delive'ring a rinsing liquid upon the skein loop while stretched over the iirst pressure roller and While continuing the alternate rotation.

5. The -method las in claim 3, including the steps of successively delivering firstly a wetting liquid, secondly a soap solution, and thirdly a .rinsing liquid upon the skein loop While stretched over the pressure and tension rollers and while continuing the Aalternate rotation.

6. The method as in claim 3, in which the indenting under `perpendicular light.

material comprises sharp particles of material harder than Zon jthe'Moh scale, and present as a slurry having a particles.

11. The method as in claim 3, in which the pressure is about445Y tov360pounds per effective inch of length of a pressure roller.

12;'The method of dulling nylon and like -tibers in skeins, which comprises kneading the fibers of a skein 'loop between yielding roller surfaces under a pressure ofk 45 to'360 pounds per effective inch of length thereof, inthefpresence of a slurry of finely divided indenting material enmeshed with the iibers, and continuing the kneading for eecting 1indentation in Vthe s ubstantial absence of removal of surface material from Athe bers, until the light reflectance Yvalue has increased at least 25 percent under parallel light.

13. The method of dulling nylon and like fibers in skeins, which comprises ykneading the fibers of a skein loop between yielding roller surfaces under a pressure of 45Qto 360-p'ounds per effective inch of length thereof, in the presence of a slurry of nelydivided indenting material enmeshed with the bers, and continuing the kneading for eiectingindentationin the substantial absence of removal of surface material from the iibers, until the light reectance value has decreased at least 20 vpercent 14. The method of dulling nylon and like bers in skeins, which comprises kneading the fibers of a skein loop betweenyielding roller surfaces under a pressure of 45 to 360 .pounds per effective inch of length thereof, in the presence. cfa slurry of nely divided indenting material enmeshed with thebers, and continuing the kneading for eifectingindentation in the substantial absence of removal of surface material from the fibers, until the ratio of reflectance values for'parallel and for perpendicular light has changed at least 15 percent relative to said values with the untreated fibers.

References Cited in-the file of this patent UNITED STATES PATENTS 1,890,643 Ellis et al. Dec. 13, 1932 V1,957,508 Taylor May 8, 1934 ,2,077,283 Taylor et al Apr. 13, 1937 2,251,508 Watson Aug. 5, 1941 .2,322,094 Newhard June l5, 1943 2,325,060 Ingersoll July 23, 1943 2,505,033 Elvin et al. Apr. 25, 1950 2,561,133 Petkewicz July 17, 1951 2,592,161 Lorig Apr. 8, 1952 FOREIGN PATENTS 335,204 Great Britain Sept. 15, 1930 556,252 Great Britain Sept. 27, 1943 713,276 Great Britain Aug. 11, 1954 737,928 France Oct. 10, 1932 

